I Got this out of another group forum,I think it is being stretched out of porportion in that they think that President Bush is going to shut down the GPS Satts. alltogether.
But if you read it you will see it is only in certian situations.
A NATIONAL EMERGENCY

Bush Prepares for Possible GPS Shutdown

WASHINGTON (AP) - President Bush has ordered plans for temporarily
disabling the U.S. network of global positioning satellites during a
national crisis to prevent terrorists from using the navigational
technology, the White House said Wednesday.

Any shutdown of the network inside the United States would come under
only the most remarkable circumstances, said a Bush administration
official who spoke to a small group of reporters at the White House
on condition of anonymity.

The GPS system is vital to commercial aviation and marine shipping.

The president also instructed the Defense Department to develop plans
to disable, in certain areas, an enemy's access to the U.S.
navigational satellites and to similar systems operated by others.
The European Union is developing a $4.8 billion program, called
Galileo.

The military increasingly uses GPS technology to move troops across
large areas and direct bombs and missiles. Any government-ordered
shutdown or jamming of the GPS satellites would be done in ways to
limit disruptions to navigation and related systems outside the
affected area, the White House said.

``This is not something you would do lightly,'' said James A. Lewis,
director of technology policy for the Washington-based Center for
Strategic and International Studies. ``It's clearly a big deal. You
have to give them credit for being so open about what they're going
to do.''

President Clinton abandoned the practice in May 2000 of deliberately
degrading the accuracy of civilian navigation signals, a technique
known as ``selective availability.''

The White House said it will not reinstate that practice, but said
the president could decide to disable parts of the network for
national security purposes.

The directives to the Defense Department and the Homeland Security
Department were part of a space policy that Bush signed this month.
It designates the GPS network as a critical infrastructure for the
U.S. government. Part of the new policy is classified; other parts
were disclosed Wednesday.

The White House said the policies were aimed at improving the
stability and performance of the U.S. navigation system, which Bush
pledged will continue to be made available for free.

The U.S. network is comprised of more than two dozen satellites that
act as beacons, sending location-specific radio signals that are
recognized by devices popular with motorists, hikers, pilots and
sailors.

Bush also said the government will make the network signals more
resistant to deliberate or inadvertent jamming.

I can remember back when I first became interested in GPS technology and started researching what would become my eventual purchase, a Garmin GPS II+(which I still use today as my primary geocaching tool). Selective availability was in effect and I am almost positive that it was quoted somewhere on a board or a newsgroup that the government could deactivate the satellites at any time given national security issues. To me, this has always stuck in my mind as being the normal practice for technology like this. Its certainly simple enough for the military to manage the sats by uplinking the required data. I can only imagine that the military could easily turn them off if need be.